What type of AM layer construction method involves creating an entire layer at once?

The method that involves creating an entire layer at once is 3D stacking. In additive manufacturing, or AM, this process allows for the simultaneous construction of a complete layer, integrating all necessary features in one step. This approach can significantly enhance production efficiency and is advantageous for printing complex geometries.

In contrast, the other options represent different methodologies or aspects of additive manufacturing that either focus on different construction techniques or do not align with the principle of layer creation described in the question. For instance, slicing involves dividing a 3D model into horizontal layers that are built sequentially, not simultaneously. Layer fusion refers to the process of bonding layers together, which is a step that occurs after the layers are created. The term "2D channel" is not typically used to describe a method of layer construction in additive manufacturing, so it does not apply within this context.

Understanding these distinctions clarifies why 3D stacking is the appropriate choice for the creation of whole layers simultaneously in additive manufacturing processes.